Corrugated paper board form for concrete voids



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CORRUGATED PAPER BOARD FORM FOR CONCRETE VOIDS 1 Filed Sept. 1. 19s? J z'sh'eets-sheet'z INVENTOR.

CHARLES HAm BY SQAAofm A UWGM W Y United States Patent Office 3,512,747 Patented May 19, 1970 3,512,747 CORRUGATED PAPER BOARD FORM FOR CONCRETE VOIDS Charles H. Stark, Waterville, Ohio, assignor to Owens- Illinois, Inc., a corporation of Ohio Filed Sept. 1, 1967, Ser. No. 665,158

Int. Cl. B28!) 7/34 US. Cl. 249-134 Claims ABSTRACT OF THE DISCLOSURE This application discloses a form for defining an clongated void in a poured concrete structure, particularly a concrete box beam, which may be constructed in its entirety from a multiplicity of sheets of corrugated fiberboard, or similar foldable, sheet-like material. The basic element of the void form comprises at least two primary sheets, each having a length corresponding to that of the desired void and being transversely foldable to conform to the desired cross-sectional configuration of portions of the void, the longitudinal edges of each such sheet being folded inwardly and lying in abutment with a similarly folded longitudinal edge of another sheet so that the sheets collectively define the desired void configura tion. The sheets are held in assembly and reinforced by a plurality of reinforcing pads each of which is contured to be snugly insertable in the space collectively defined by the primary sheets and each pad having inwardly extending slots in its periphery respectively snugly engagable with the abutting longitudinal edges of the primary sheets to hold the same in assembly.

This invention relates to a form for defining voids in poured concrete structures, more particularly to a void form which may be fabricated in its entirety from a multiplicity of sheets of corrugated paper board by simple folding and assembling operations, thereby permitting the assembly of the void forms at the site of the concrete pouring operation.

In the art of producing building structures and components through the utilization of poured concrete, it has been long recognized that substantial voids may be created in such concrete structures, thereby substantially reducing the overall weight and cost of such structures, without any substantial decrease in the effective strength of such structure. This concept has been universally applied in the manufacture of reinforced concrete box beams. Inasmuch as the stresses to which such box beams are subjected in service are generally concentrated in the cross-sectional areas of the beam remote from the center, it has been common practice to form each beam with a substantially hollow central portion or void.

Wood and metal materials have heretofore been utilized in forms to define such voids. In many poured structures it is impossible to remove the void forms from the poured structure; therefore, the total cost and weight of the void form become items of substantial importance and, in particular, make the utilization of wood and metal void forms for concrete box beams quite impractical. If

an appropriate form could be produced at the pour site from sheets of corrugated paper board or any other fibrous sheet material, the cost of such form would be substantially less than that of wood or metal and, more importantly, the additional weight incorporated in the concrete structure, if it is necessary to leave the form in place, would be substantially decreased; however, it is difiicult to construct a void form from corrugated paper with the requisite strength to withstand the very heavy loading imposed by the concrete slurry during the pouring and setting operations.

Acordingly, it is an object of this invention to provide an improved void form for poured concrete structures.

A particular feature of this invention is to provide a void form for concrete structures which may be fabricated in its entirety from a multiplicity of sheets of corrugated fiberboard or similar sheet material and which will provide the requisite strength required in such form at a minimum cost and weight.

Other objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description taken in conjunction with the annexed sheets of drawings on which there are shown two embodiments of this invention.

On the drawings:

FIG. 1 is a perspective View illustrating the initial as sembly of material sheets into a void form configuration in accordance with this invention.

FIG. 2 is a perspective view of a partially assembled void form embodying this invention.

FIG. 3 is a perspective view of another embodiment of this invention illustrating the assembly of a plurality of void form components into a larger form ur. it.

Refering to FIGS. 1 and 2, reference numerals 10 and 11 respectively indicate primary sheets of corrugated paper board or similar fibrous material which are assembled into a void form component 1 in accordance with this invention. In the specific example illustrated, the primary sheets 10 and 11 are of substantially identical configuration which is desirable from the standpoint of reducing the required inventory of such sheets, but it is not essential to the practice of this invention. Each sheet 10 and 11 is provided with a plurality of longitudinal scores or fold lines as indicated at 10a and 11a respectively to permit such sheet to be folded to conform to a portion of the cross-sectional configuration of the desired void. Additionally, score lines or grooves 10b and 11b are respectively provided immediately adjacent each longitudinal edge 10c and of each primary sheet 10 and 11 to permit such edges to be respectively folded inwardly to a position substantially perpendicular to the adjacent portion of the respective sheet.

Primary sheets 10 and 11 are then assembled by placing two of the inturned longitudinal edges 10c and 110 in juxtaposition and then engaging such juxtaposed edges at spaced intervals along the lengths of the sheets by a plurality of reinforcing pads 15. Each pad 15 is formed from heavy weight corrugated paper board or similar relatively rigid material and has a cross sectional configuration corresponding to the desired interior space to be collectively defined by sheets 10 and 11 when assembled. Each pad 15 is provided with slots 15a extending inwardly from its perphery which are constructed and arranged to interengagingly cooperate with aligned slots 10d and 11a respectively provided in the juxtaposed longitudinal edges 10c and 11c of sheets 10 and 11. After the one pair of longitudinal edges 10c and 11c are thus interengaged by the slotted pads 15, then the remaining portions of each primary sheet 10 and 11 are folded around the supporting pads 15 to bring the opposite pair of longitudinal edges 10's and 110 into juxtaposition and to insert same in the remaining slots 15a of the reinforcing pads 15.

Those skilled in the art will recognize that more than two primary sheets can be utilized, if desired, to cooperatively and collectively define the void form so long as the inwardly turned longitudinal edges of successive sheets are successively juxtaposed and the number of retainin gslots 15a provided in each reinforcing pad 15 in equal to the number of primary sheets.

The number of reinforcing pads 15 that are employed along the length of the void form is, of course, dependent upon the weight, and hence the strength, of the paper utilized in the primary sheets. In any event, the weight of paper employed and the number and spacing of the reinforcing pads are selected to produce a form having sufiicient strength to withstand the compressive force of the poured concrete in the particular structure in which the void form is to be utilized.

Referring to FIG. 2, the void form component 1 heretofore described is finished as a completed form by longitudinal insertion of same within the corresponding shaped interior of a tube or sleeve 2. Sleeve 2 is formed from a single sheet of corrugated paper board or similar fibrous material by longitudinal scoring or grooving such sheet, as indicated at 2a, so as to permit the sheet to be folded into a cross-sectional configuration identical to that of the void form component 1. The longitudinal edges 2b of the sheet are secured together by any conventional means, such as by stitching, stapling or adhesive, thus retaining same in the sleeve configuration.

After insertion of the void form component 1 within the interior of the sleeve 2, a pair of end caps 3, formed in conventional fashion by folding a corrugated sheet, are respectively applied to the ends of the sleeve 2.

The outer surfaces of sleeve 2 and end caps 3 are preferably coated or treated with a moisture resistant material to eliminate weakening of the form by the moisture in the freshly poured concrete.

It will be apparent to those skilled in the art that the compressive strength of the void form shown in FIG. 2 will be reduced as the overall cross-sectional size of the form is increased. Accordingly, in those applications where voids of large cross section are required, or extra heavy concrete loads must be withstood, the void form construction shown in FIG. 3 can be expeditiously employed. In this construction, a plurality of void form components 4 constructed in generally the same manner as the components 1 heretoforce described are assembled in side-by-side lengthwise contiguous relationship. The cross-sectional configuration of each. of the void form components thus corresponds to only a portion of the crosssectional configuration of the desired void.

In the example specifically illustrated in FIG. 3, four such void form components 4 are employed, with each component defining approximately one-quarter of the desired void. The void form components 4 are held in assembly, and hence in mutually reinforcing relationship by insertion thereof in an outer sleeve 5 which. is constructed in the same fashion as the outer sleeve 2 previously described but is, of course, of much larger crosssectional configuration. A pair of folded corrugated board end caps 6 are then respectively secured to each end of outer sleeve 4 after the void form components have been inserted therein.

In the modification of FIGS. 1 and 2, the inter-locking action of the slots 15a in the reinforcing pads 15 with the aligned slots 10d and 11a in the longitudinal edges 10c and lie inherently prevents longitudinal displacement of the pads 15 relative to the primary sheets 10 and 11. A further anchoring of the reinforcing pads 16 against longitudinal displacement may be conveniently provided in the multi-component void form construction of FIG. 3. It will be noted that each of the void form components 4 is provided with a 45 degree angular wall 4a on the innermost corner of the void form component. Thus, when the four void form components 4 are assembled in longitudinally contiguous relationship, a generally rectangular opening 7 is defined in the center of the cluster of such void form components. Each of the walls 4a which defines this space is then provided with a plurality of longitudinally spaced slots 4b which are respectively located in cross-sectional alignment with the aligned slots 4d in the inturned longitudinal edges 4c of 4 sheets 4a. Each of the reinforcing pads 16 is then formed with a rectangular corner 16c which projects through the adjacent slot 4b and effects a further longitudinal anchoring of the pad 16.

Other modifications of this invention will become apparent to those skilled in the art from the foregoing description, and the scope of this invention is intended to be limited solely by the following claims.

I claim:

1. A concrete void form comprising, in combination:

an elongated sleeve of corrugated paper board;

a plurality of pre-assembled, substantially identical modular form components disposed in side-by-side continguous relationship with their longitudinal axes parallel to one another and parallel to the longitudinal axis of said sleeve, said plurality of components being snugly surrounded by said elongate sleeve with each form component thereof comprisat least two primary sheets of corrugated paper board each having a length corresponding to that of the desired void and being longitudinally foldable to conform to portions of the desired cross-sectional configurations of the void, the longitudinal edges of each primary sheet being folded inwardly to an angular position relative to the adjacent portions of the sheet and each longitudinal edge of each primary sheet having a series of spaced, inwardly extending slots and lying in abutment with a longitudinal edge of another of said primary sheets with the slots in abutting longitudinal edges being aligned, whereby said primary sheets collectively define the desired void configuration, and plurality of reinforcing pads, each contoured to be snugly insertable within the space collectively defined by the primary sheets, each pad having inwardly extending slots in its periphery respectively snugly engagable with corresponding slots. in said abutting longitudinal edges of said primary sheets, thereby holding same in assembly, said pads being spaced along the length of the assembled primary sheets; and

a pair of corrugated paper board end caps respectively secured to the ends of said elongate sleeve.

2. A concrete void form according to claim 1 wherein said form comprises four of said modular form components said components being disposed in a rectangular array within said sleeve.

3. A concrete void form according to claim 2 wherein each of said form components has, in transverse section, six sides of substantial length, with four of said sides defining two diametrically opposed included angles substantially equal to each and with one of the other of such sides defining, with one other such side of each of the other form components, a four-sided opening extending centrally through said rectangular array of form components.

4. A concrete void form according to claim 3 wherein the primary sheets of corrugated paper board which are comprised by each form component are substantially identical to one another, wherein all portions of each reinforcing pad comprised by each form component are totally enclosed within the primary sheets comprised by the form component, and wherein the four-sided opening which extends centrally through said rectangular array of form components is substantially unobstructed.

5. A concrete void form according to claim 3 wherein said one other of such sides of each of said form components is provided with a plurality of transversely extending longitudinally-spaced slots corresponding in number and location to the reinforcing pads contained in such form component, and wherein each reinforcing pad comprises an integral portion which projects through one of 5 6 said slots to positively position each of said pads longitu- OTHER REFERENCES diflany of said form component Engineering News-Record advertisement Jay-Tubes For Hollow Slab Bridges; NOW. 5, 1959; p. 40. References C'ted Engineering News-Record article Prefab Forms for UNITED STATES TS 5 Beam Voids; Aug. 9, 1962: Vol 169, No. 6, p. 40.

2 92 1 3 3 19 0 Deutsclm I. HOWARD FLINT, JR., Primary Examiner 3,024,513 3/1962 Shuxteau et al. US. Cl. X.R.

3,358,960 12/1967 Oliver et 211. 249-183, 184 

